That sounds good to me, though Matt and I will be in town on Thursday.  I'm thinking we can hang out at the hotel pool Thursday evening, depending on when you guys get in.
On Friday morning/afternoon, maybe we can go to this 
splashpad.  It's $3/person for non Marietta residents.  
For Saturday, I'm not sure if the kids will want to stay for a full round.  Maybe we can skip DG and just do Saturday at E-casa.  Board games/movies, and Water slide shenanigans.
Do you have a go-to place for the bounce houses?  
AstroJump seems pretty good.  Though I don't think they allow their 4-in-1 or 7-in-1 to be water, so we'd have to get a water slide.  The only issue is that the smaller ones may not has as much fun.  
This one may be a decent compromise.